Impact and sound analysis for golf equipment

ABSTRACT

Golf performance and equipment characteristics may be determined by analyzing the impact between a golf ball and an impacting surface. In some examples, the impacting surface may be a golf club face. The impact between the golf ball and the surface may be measured based on sound and/or motion sensors (e.g., gyroscopes, accelerometers, etc.). Based on motion and/or sound data, various equipment-related information including golf ball compression, club head speed and impact location may be derived. Such information and/or other types of data may be conveyed to a user to help improve performance, aid in selecting golf equipment and/or to insure quality of golfing products.

RELATED APPLICATION DATA

This is a continuation of U.S. patent application Ser. No. 15/452,209filed on Mar. 7, 2017, which is a continuation-in-part of U.S. patentapplication Ser. No. 13/838,690 filed Mar. 15, 2013, now U.S. Pat. No.9,612,253 issued Apr. 4, 2017, and a continuation-in-part of U.S. patentapplication Ser. No. 13/839,541 filed Mar. 15, 2013, now U.S. Pat. No.9,607,752 issued Mar. 28, 2017, all of which are entirely incorporatedherein by reference.

TECHNICAL FIELD

Aspects relate to analyzing impact data for golf equipment. Moreparticularly, aspects described herein relate to determining variousimpact and equipment characteristics based on impact data.

BACKGROUND

Golf is enjoyed by a wide variety of players—players of differentgenders and dramatically different ages and/or skill levels. Golf issomewhat unique in the sporting world in that such diverse collectionsof players can play together in golf events, even in direct competitionwith one another (e.g., using handicapped scoring, different tee boxes,in team formats, etc.), and still enjoy the golf outing or competition.These factors, together with the increased availability of golfprogramming on television (e.g., golf tournaments, golf news, golfhistory, and/or other golf programming) and the rise of well known golfsuperstars, at least in part, have increased golf's popularity in recentyears, both in the United States and across the world.

Golfers at all skill levels seek to improve their performance, lowertheir golf scores, and reach that next performance “level.”Manufacturers of all types of golf equipment have responded to thesedemands, and in recent years, the industry has witnessed dramaticchanges and improvements in golf equipment. For example, a wide range ofdifferent golf ball models now are available, with balls designed tocomplement specific swing speeds and/or other player characteristics orpreferences, e.g., with some balls designed to fly farther and/orstraighter; some designed to provide higher or flatter trajectories;some designed to provide more spin, control, and/or feel (particularlyaround the greens); some designed for faster or slower swing speeds;etc. A host of swing and/or teaching aids also are available on themarket that promise to help lower one's golf scores.

Being the sole instrument that sets a golf ball in motion during play,golf clubs also have been the subject of much technological research andadvancement in recent years. For example, the market has seen dramaticchanges and improvements in putter designs, golf club head designs,shafts, and grips in recent years. Additionally, other technologicaladvancements have been made in an effort to better match the variouselements and/or characteristics of the golf club and characteristics ofa golf ball to a particular user's swing features or characteristics(e.g., club fitting technology, ball launch angle measurementtechnology, ball spin rates, etc.).

Improvement in golf may also be achieved by studying a player's swingand adjusting his or her posture and swing characteristics to maximizemomentum, head speed, lie angle, impact location and the like. However,it may be difficult for a user to independently to determine head speedor an impact location of the golf ball against the golf club face. Whilevarious technologies for detecting these characteristics exist, they maybe costly or difficult to use.

BRIEF SUMMARY

The following presents a general summary of aspects of the disclosure inorder to provide a basic understanding of the invention and variousfeatures of it. This summary is not intended to limit the scope of theinvention in any way, but it simply provides a general overview andcontext for the more detailed description that follows.

Aspects described herein provide systems, methods, computer readablemedium storing computer readable instructions for receiving data for animpact between a golf ball and an impact surface, analyzing the impactdata to determine one or more characteristics of the impact, andgenerating an output based on the determined impact characteristic(s).The impact data may be received based on detecting a sound generated bythe impact. The amplitudes and frequencies of the audio signal may beanalyzed to determine various characteristics such as a magnitude ofcompression of the golf ball, an impact location on the surface and/or aspeed with which the surface impacts the golf ball. In some examples,the surface may correspond to a surface of a golf club head. Thedetermined characteristics may be used, in some arrangements, todetermine a golf ball impact location on the surface of the golf clubhead. Alternatively or additionally, the characteristics may be used toidentify a type of golf ball best suited for a particular user (and/or,e.g., golf club head speed). In yet other arrangements, the determinedcharacteristics, such as golf ball compression, may be used to insurethe quality of a golf ball.

According to some aspects, the impact data may include gyroscopic and/oraccelerometric data of the golf club head. Using such data, the impactlocation may also be determined with or without the use of sound.

According to other aspects, a mobile communication device may beconfigured to detect golf ball impact sounds and to determine thevarious impact characteristics. In one example, a mobile communicationdevice may record the sound of a golf ball impact and to visuallyindicate the golf ball impact location against a golf club head.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention and certainadvantages thereof may be acquired by referring to the followingdetailed description in consideration with the accompanying drawings, inwhich:

FIG. 1 illustrates an example golf analysis system according to one ormore aspects described herein.

FIG. 2 illustrates an example computing device according to one or moreaspects described herein.

FIG. 3 illustrates an example process by which a golf ball impact may beanalyzed to determine one or more performance characteristics accordingto one or more aspects described herein.

FIG. 4 illustrates an example process for determining a club head speedusing sound analysis according to one or more aspects described herein.

FIG. 5 illustrates example golf balls that may be used to determine golfclub head speed according to one or more aspects described herein.

FIG. 6 illustrates an example process for determining impact locationbased on impact sound analysis according to one or more aspectsdescribed herein.

FIG. 7 illustrates an example division of impact location areas on aclub face according to one or more aspects described herein.

FIG. 8 illustrates an example interface for displaying an impactlocation according to one or more aspects described herein.

FIG. 9 illustrates an example process for determining impact locationusing motion sensor data according to one or more aspects describedherein.

FIG. 10 illustrates an example golf club head according to one or moreaspects described herein.

FIGS. 11A-11D illustrates example sound signals and referencefrequencies according to one or more aspects described herein.

FIG. 12 illustrates an example process for testing golf balls usingsound analysis according to one or more aspects described herein.

FIG. 13 illustrates an example apparatus configured to determine golfball quality and to sort golf balls based on the determined qualityaccording to one or more aspects described herein.

The reader is advised that the attached drawings are not necessarilydrawn to scale.

DETAILED DESCRIPTION

In the following description of various example structures in accordancewith the invention, reference is made to the accompanying drawings,which form a part hereof, and in which are shown by way of illustrationvarious example connection assemblies, golf club heads, and golf clubstructures in accordance with the invention. Additionally, it is to beunderstood that other specific arrangements of parts and structures maybe utilized, and structural and functional modifications may be madewithout departing from the scope of the present invention. Also, whilethe terms “top,” “bottom,” “front,” “back,” “rear,” “side,” “underside,”“overhead,” and the like may be used in this specification to describevarious example features and elements of the invention, these terms areused herein as a matter of convenience, e.g., based on the exampleorientations shown in the figures and/or the orientations in typicaluse. Nothing in this specification should be construed as requiring aspecific three dimensional or spatial orientation of structures in orderto fall within the scope of this invention.

A. General Description of Background Information Relating to thisInvention

Properly fitting a golfer with clubs and golf balls suited to his or herswing can help the golfer make better and more consistent contact withthe ball during a swing and help the golfer reduce his or her score.Additionally, having additional information regarding how (e.g., where)a golfer is hitting a golf ball with a golf club may allow the golfer tobetter improve his or her swing. Several factors affect a golfer'sswing. For example, the lie angle, the loft angle, type of golf ball,and the club head angle of the club during impact with a golf ballgreatly affect the trajectory of the ball.

Various mechanisms exist to help a user evaluate his or her swing and,particularly, to identify an impact location on a club face. However, asnoted above, such systems may be difficult or costly to use. Forexample, some systems require a user to place impact tape or paper onthe golf club face. Upon hitting a golf ball, the user would then beable to identify the location where he or she made contact with theball. Impact tape, as can be appreciated, must be replaced per use.Moreover, impact tape must be manually installed on the golf club eachthe user wishes to evaluate his or her swing and hit. As such, theefficiency and ease of using impact tape might detract from itsadoption.

Other player swing analysis systems may involve the golfer visiting aspecialized facility having high cost equipment for recording and/ormeasuring various characteristics of the player's swing. In one example,such systems are used to measure golf club head speed during a user'sswing using motion or speed sensors for either the golf ball or the golfclub head or both. Once the user's club head speed is known, the usermay be fitted with appropriate balls for his or her head speed to helpimprove the player's performance. For example, some types of golf ballsare designed for particular speed ranges, travelling farther for thoseparticular speeds. Again, however, the cost of such an evaluation may beprohibitive to some players.

Accordingly, systems, methods, computer readable media storing computerreadable instructions that will reduce the costs and improve theefficiencies of measuring various golf equipment and performancecharacteristics would be a welcome advance in the art.

B. General Description of Golf Ball Impact Analysis According toExamples of the Invention

In general, as described above, aspects described herein relate todetermining various golf equipment characteristics based on impactanalysis. For example, using impact analysis, a system, method, computerreadable media and the like may be able to determine club head speed,check the quality of a golf ball, determine an impact location betweenball and club and the like.

FIG. 1 illustrates an example system and environment 100 in whichvarious aspects described herein may be used and implemented. Forexample, characteristics of golf equipment may be determined usingconsumer electronic equipment including a personal computer 103 andmobile communication device 105. Mobile communication device 105 maycomprise a tablet computer, a personal data assistant (PDA), asmartphone, and/or combinations thereof. Personal computer 103 mayinclude laptop computers or desktop computers. Each of devices 103 and105 may be connected to network 107 to a variety of other devices anddestinations including server 109. Server 109 may be configured tocollect data from various user devices as well as to distributeinformation such as fitness challenges, golf recommendations, productoffers and the like. Devices 103 and 105 may include network interfacesthat are either wired or wireless or may have both wired and wirelessconnection interfaces. Wireless connections may be short range or longrange and may include Wi-Fi, BLUETOOTH, infrared, satellitecommunications, cellular communications and the like. Some devices(e.g., device 105) may include multiple network interfaces and have thecapability of transmitting and receiving information over differentinterfaces depending on a destination/source, time of day, type ofinformation being sent/received and the like. Components of devices 103and 105 and server 109 are discussed in further detail below.

As noted, devices 103 and 105 may be equipped to detect various datafrom a golf ball impact and to determine various golf equipmentcharacteristics therefrom. In one example, an impact sound signal may beused to determine (e.g., calculate) a variety of golf equipmentcharacteristics, including impact location, club head speed, golf ballquality and the like. Accordingly, as shown with equipment arrangement111, devices 103 and 105 may be configured to record a sound generatedby the impact between club 113 and ball 115. As described in furtherdetail below, the impact sound signal may provide various frequenciesindicative of the location of the impact location and/or the golf clubspeed at impact. Each of devices 103 and 105 may have an application orprogram to evaluate the sound data and to provide various outputincluding club speed, impact location and product recommendations.

Equipment arrangement 117 illustrates a quality check system for golfballs. The golf balls may be launched, dropped or otherwise released soas to impact a surface and generate an impact sound. This sound mayindicate an amount of compression experienced by the golf ball uponimpact. For example, since golf balls are required to have a certainrange of compression with a given force, the acceptability of the golfball may be verified based on the sound of the golf ball impact. As willbe described in further detail, the ball may be launched, dropped orreleased from a known distance or height so that the test force is knownand consistent during each test, and the resulting impact soundrecorded. In one example, each golf ball may be released from a heightof 5 feet. Other heights and distances may be used depending on variousfactors. The amount of compression may then be calculated based on therecorded sound.

According to yet other aspects, the golf club 113 may include one ormore non-acoustic sensors such as gyroscopes and/or accelerometers.Gyroscopes may provide data indicating the angular velocity about aparticular axis. In one arrangement, club 113 may include threegyroscopes for measuring angular velocity about the x, y and z-axes.These angular velocities may also provide an indication of the impactlocation. For example, and similar to the analysis of sound signals, thegyroscopic signals from the golf club 113 may be analyzed to determinethe frequency content. The energy associated with specific frequenciesmay then be evaluated against previously determined angular velocitycharacteristics (e.g., in the form of frequency response spectra such asFast Fourier Transforms, also known as FFTs) in determining a locationon the club 113 face where the golf ball 115 impacted. A similar processmay be implemented using measured club accelerations. This analysis maybe performed by club 113, device 103, device 105, server 109 and/or acombination thereof.

FIG. 2 shows one illustrative example of a computing device 201 that canbe used to implement various aspects and features described herein. Forexample, computing device 201 may act as device 103, device 105, server109 and/or a computing module within club 113 or ball 115. As seen inthis figure, the computing device 201 has a computing unit 203. Thecomputing unit 203 typically includes a processing unit 205 and a systemmemory 207. The processing unit 205 may be any type of processing devicefor executing software instructions, but will conventionally be amicroprocessor device. The system memory 207 may include both aread-only memory (ROM) 209 and a random access memory (RAM) 211. As willbe appreciated by those of ordinary skill in the art, both the read-onlymemory (ROM) 209 and the random access memory (RAM) 211 may storesoftware instructions for execution by the processing unit 205.

The processing unit 205 and the system memory 207 are connected, eitherdirectly or indirectly, through a bus 213 or alternate communicationstructure to one or more peripheral devices. For example, the processingunit 205 or the system memory 207 may be directly or indirectlyconnected to additional memory storage, such as the hard disk drive 217,the removable optical disk drive 219. Additional buses may be includedas needed or desired. Computing device 201 may further use or interfacewith other memory storage mediums such as solid state drives, removablemagnetic disk drives and flash memory cards. The processing unit 205 andthe system memory 207 also may be directly or indirectly connected toone or more input devices 221 and one or more output devices 223. Theinput devices 221 may include, for example, a keyboard, touch screen, aremote control pad, a pointing device (such as a mouse, touchpad,stylus, trackball, or joystick), a scanner, a camera or a microphone.The output devices 223 may include, for example, a monitor display,television, printer, stereo, or speakers.

Still further, the computing unit 203 may be directly or indirectlyconnected to one or more network interfaces 215 for communicating with anetwork. This type of network interface 215, also sometimes referred toas a network adapter or network interface card (NIC), translates dataand control signals from the computing unit 203 into network messagesaccording to one or more communication protocols, such as theTransmission Control Protocol (TCP), the Internet Protocol (IP), and theUser Datagram Protocol (UDP). Network adapters may be wireless or wiredor combinations thereof. These protocols are well known in the art, andthus will not be discussed here in more detail. An interface 215 mayemploy any suitable connection agent for connecting to a network,including, for example, a wireless transceiver, a power line adapter, amodem, or an Ethernet connection. Connection agents may similarly bewireless or wired or a combination thereof. Accordingly, using interface215, computing device 201 may be able to access wide area networks suchas the Internet in addition to local area networks. Data such as soundsignals, calculated impact location information, golf ball qualityinformation, club head speed data and the like may be transmitted to orreceived from local or remote network sources (not shown).

It should be appreciated that, in addition to the input, output andstorage peripheral devices specifically listed above, the computingdevice may be connected to a variety of other peripheral devices,including some that may perform input, output and storage functions, orsome combination thereof. For example, the computing device 201 may beconnected to a digital music player, such as an IPOD® brand digitalmusic player available from Apple, Inc. of Cupertino, Calif. As known inthe art, this type of digital music player can server as both an outputdevice for a computer (e.g., outputting music from a sound file orpictures from an image file) and a storage device. In addition, thistype of digital music player also can serve as an input device forinputting recorded athletic information such as golf swing information.Connections and interfaces may be wireless, wired or combinationsthereof.

In addition to a digital music player, the computing device 201 may beconnected to or otherwise include one or more other peripheral devices,such as a telephone. The telephone may be, for example, a wireless“smartphone.” As known in the art, this type of telephone communicatesthrough a wireless network using radio frequency transmissions. Inaddition to simple communication functionality, a “smart phone” may alsoprovide a user with one or more data management functions, such assending, receiving and viewing electronic messages (e.g., electronicmail messages, SMS text messages, etc.), recording or playing back soundfiles, recording or playing back image files (e.g., still picture ormoving video image files), viewing and editing files with text (e.g.,Microsoft Word or Excel files, or Adobe Acrobat files), etc. Because ofthe data management capability of this type of telephone, a user mayconnect the telephone with the computing device 201 so that their datamaintained may be synchronized.

Of course, still other peripheral devices may be included with orotherwise connected to a computing device 201 of the type illustrated inFIG. 2, as is well known in the art. In some cases, a peripheral devicemay be permanently or semi-permanently connected to the computing unit203. For example, with many computers, the computing unit 203, the harddisk drive 217, the removable optical disk drive 219 and a display aresemi-permanently encased in a single housing. Still other peripheraldevices may be removably connected to the computing device 201, however.The computing device 201 may include, for example, one or morecommunication ports through which a peripheral device can be connectedto the computing unit 203 (either directly or indirectly through the bus213). These communication ports may thus include a parallel bus port ora serial bus port, such as a serial bus port using the Universal SerialBus (USB) standard or the IEEE 1394 High Speed Serial Bus standard(e.g., a Firewire port). Alternately or additionally, the computingdevice 201 may include a wireless data “port,” such as a Bluetoothinterface, a Wi-Fi interface, an infrared data port, or the like.

It should be appreciated that a computing device employed accordingvarious examples of the invention may include more components than thecomputing device 201 illustrated in FIG. 2, fewer components than thecomputing device 201, or a different combination of components than thecomputing device 201. Some implementations of the invention, forexample, may employ one or more computing devices that are intended tohave a very specific functionality, such as a digital music player orserver computer. These computing devices may thus omit unnecessaryperipherals, such as the network interface 215, removable optical diskdrive 219, printers, scanners, external hard drives, etc. Someimplementations of the invention may alternately or additionally employcomputing devices that are intended to be capable of a wide variety offunctions, such as a desktop or laptop personal computer. Thesecomputing devices may have any combination of peripheral devices oradditional components as desired.

A computing device such as device 201 may be used to calculate orotherwise determine swing characteristics including an impact locationbetween a golf ball and a golf club, an amount of compressionexperienced by a dropped golf ball and/or a head speed of a golf clubduring a player's swing. In some arrangements, these calculations ordeterminations may be based on sound that is detected through, forexample, a microphone.

FIG. 3 illustrates an example method by which information relating togolf equipment may be generated as output based on golf ball impactdetection. In step 301, a computing device (e.g., device 201 of FIG. 2)may receive impact data. As noted herein, impact data may include avariety of information including detected sound, data from sensors on agolf club or golf ball (or both), data from a sensor external to thegolf equipment and the like and/or combinations thereof. The data may berecorded, in some examples, by a device such as laptop 103 or mobilecommunication device 105 (both of FIG. 1). Additionally oralternatively, the user may be prompted to create the golf ball impactby an instruction from the computing device. As such, a user might onlybegin swinging at the golf ball upon receiving a correspondinginstruction from the computing device.

In step 305, the computing device may further analyze the receivedimpact data by performing various calculations, comparisons,mathematical functions and the like. In one example, a recorded soundsignal may be processed using a Fourier Transform to determine theresponse frequencies and the amplitudes at each frequency. Alternativelyor additionally, the computing device may compare the impact data orother data derived from the analysis of the impact data to determinevarious attributes or characteristics of the impact.

In step 310, the computing device may generate an output based on theanalysis of the impact data. The output may include visuals, audio data,textual information and/or haptic feedback. According to one aspect, theoutput may include an indication of an impact location. According toanother aspect, the output may include an indication as to whether agolf ball passed a quality control check. According to yet anotheraspect, the output may include a club head speed and/or a recommendationfor a type of golf ball to use. As one might imagine, a variety of othertypes of output and information may be provided to a user based on theanalysis of the impact data.

1. Example Golf Club Head Speed Determination and Golf Ball Fitting

Golf club head speed may be important in evaluating a player's swing andperformance. For example, the faster a player's club head speed, thefarther a ball may potentially fly. In some instances, however, a golfball may be configured to particular head speeds. Accordingly, a golfball configured for a higher head speed might not fly as far as one thatis configured for the particular head speed with which a player is ableto achieve. In order to identify the correct golf ball for the player,the club head speed must first be determined.

FIG. 4 illustrates an example method for determining club head speedwithout use of a motion sensor (e.g., speed gun). The method may includethe use of multiple golf balls, each exhibiting different constructionsand sound characteristics than the others. In one example, a computingsystem (e.g., computing device 201 of FIG. 2) may initiallydetect/receive sound data generated from hitting a first golf ball usinga golf club in step 401. The first golf ball may include a first set ofcharacteristics that cause the golf ball impact to generate a soundsignal having a predefined frequency when struck at a particular headspeed. In one example, the computing device may record the sound usingits own microphone. In another example, the computing device may receivea sound signal recorded by another device such as the golf club, astand-alone microphone, a mobile communication device (e.g., theplayer's mobile phone) or the like. The computing system may furtherdetect/receive sound data generated from hitting a second golf ballusing the golf club in step 405. The second golf ball may differ fromthe first golf ball in one or more characteristics such as materialcomposition, compression, hardness and the like. As with the first ball,the second golf ball may be configured to generate a sound signal havingthe predefined frequency when struck at another particular head speed(e.g., lower than the particular head speed of the first golf ball).

FIG. 5 illustrates example golf balls that may be used in determiningthe head speed of the player's club. Balls [A], [B], [C] and [D] may becharacterized in having cores of different sizes. The cores may beconfigured to produce a sound frequency different from frequencies thatare otherwise generated if the core is not sufficiently impacted by theclub. In one example, the outer portion 501 of each ball may be composedof a rubber material while the inner core 503 of each ball may becomposed of a resin material (e.g., HPF core). The relative sizes of theinner cores 503 allow for easier or more difficult activation of thespecified frequency. For example, the larger inner core 503 as shown ingolf ball [D] may activate at lower club head speeds (e.g., lowercompression), while the smaller inner core 503 of golf ball [A] mayrequire a high club head speed (e.g., higher compression) to trigger thespecified frequency. In some arrangements, the specified frequency mightalways be generated when any of the golf balls [A]-[D] are struck.However, the frequency might not be perceptible or extracted from thesound signal unless the frequency is of a minimum amplitude.Accordingly, the balls may be rated for different club speedscorresponding to the speed and compression required to generate thefrequency at the minimum amplitude.

The golf balls used for club speed testing and golf ball fitting may beconfigured as a set to be used with one another. For example, golf ball[A] may be rated for a first speed, while golf balls [B], [C] and [D]may be rated for second, third and fourth speeds, respectively, wherethe first speed>second speed>third speed>fourth speed. Using thispreconfigured set of golf balls, the user's golf club head speed may beappropriately determined based on detection of the specified frequency.

Golf balls [A]-[D] may be configured in other ways to achieve the sameability to differently generate the specified frequency depending onclub head speed. In one example, the golf club outer core 501 may beconstructed using different materials having different compressioncharacteristics. Accordingly, the inner core 503 of the balls, invarious examples, may be identical or substantially the same while theouter core 501 may be configured to control the amount of force and clubhead speed required to trigger the predefined frequency. Otherconfigurations may also be used to distinguish the sound-generatingcharacteristics of the golf balls.

Referring again to FIG. 4, the computing system may determine, in steps410 and 415, whether the specified frequency exists in the receivedsound signals of steps 401 and 405, respectively. The specifiedfrequency may be determined empirically based on a population of samplehits of varying speeds. In one example, a club swinging machine may beused to record sound signals at a variety of different speeds and usingthe various golf balls. The frequency characteristics of each of thesound signals for each of the golf balls may be analyzed to identify thefrequency generated by the inner core (for instance). Based on thefrequency information, the computing system may determine a club headspeed in step 420. For example, if the specified frequency is detectedfrom the second golf ball hit, but not the first golf ball hit, thecomputing system may determine that the club head speed is lower than aminimum rated club head speed of the first golf ball, but not as low asthe rated club head speed of the second golf ball. The computing systemmay further compare the amplitude of the specified frequency todetermine the corresponding club speed based on known (e.g., predefined)amplitude-club head speed relationships. For example, the specifiedfrequency registering at a first amplitude may correspond to a clubspeed of 90 mph while the specified registering at a second amplitudemay correspond to a club speed of 102 mph. Speeds and amplitudes betweenthe predefined relationship may be interpolated. Such predefinedrelationships may be generated based on the empirical data gathered inthe sample hits. Alternatively, if the specified frequency is detectedin both the first golf ball hit and the second golf ball hit, thecomputing system may determine that the club head speed is at leastgreater than the minimum rated club speed of the first golf ball.

As noted above, in some arrangements, the computing system may considerthe amplitude of the frequencies in determining whether a particularfrequency exists in a sound signal. Accordingly, if the specifiedfrequency in a sound signal does not register a minimum amplitude, thecomputing system may determine that the specified frequency was notdetected or does not exist in the sound signal. In some examples, theminimum amplitude may be defined based on an intensity of ambient noisein the environment. The ambient noise may be measured prior to the golfball hits to set the baseline minimum for the specified frequency.

In step 425, the computing system may further generate and provide agolf ball recommendation based on the determined club head speed. Asdiscussed, different golf balls may have difficult constructions andconfigurations to achieve maximum distance for a given club head speed.Accordingly, a table or other relationship may be predefined tocorrelate club head speed with particular types of golf balls. Thus,upon determining the user's club head speed, the computing system mayrecommend a corresponding type of golf ball. Other factors beyond clubhead speed may also be taken into account in generating therecommendation including club type, lie angle, gender of the player andthe like.

While the arrangements described above with respect to FIG. 4illustrates the first and second ball hits being recorded prior toanalyzing the sound signals, other sequences may be adopted. Forexample, the first ball hit may be performed followed by the analysis ofwhether the specified frequency is included in the first ball hit. Onlyif the specified frequency does not exist (or is below a specifiedminimum amplitude) might the computing system instruct the user toproceed to hit the second golf ball. Additionally or alternatively, morethan two golf balls may be used in the club head speed determinationprocess. For example, a total of 3, 4, 5, 7, 10, etc. golf balls may beused to detect club head speed. The use of more golf balls may, in someexamples, provide more golf club speed detection granularity.

According to still other arrangements, a user may be instructed to startwith a golf ball having a lowest rated club head speed and to hitadditional golf balls if the specified frequency is detected and/or isabove a maximum amplitude threshold. For example, if the specifiedfrequency is detected, but exceeds a threshold amplitude, the computingsystem might not be able to determine the corresponding club head speed.The computing system might, in some arrangements, only define club headspeed to amplitude correspondences up to a certain threshold amplitude.Accordingly, the user may be instructed to hit a second golf ball havinga higher rated club head speed to better determine the club head speed.

Using sound, a player's golf club head speed may be determined usingtypical consumer electronics. The golf club head speed may then be usedto select an appropriate golf ball to maximize the player's performance.

2. Example Impact Location Determination Using Sound

In addition to golf club head speed, sound may be used to determine alocation on a club face where a golf ball makes contact. As can beappreciated by golfers, knowing and improving upon a contact locationbetween the club and the ball may help significantly improve golfingperformance. For example, a player may better adjust his or her stance,posture, grip and the like to achieve hitting the golf ball in the“sweet spot” of the club face.

FIG. 6 illustrates an example method by which a computing system maydetermine an impact location of a golf ball on a golf club face. Thecomputing system may correspond to a mobile communication device in someexamples. In step 601, the computing system may request identificationof a user that will be hitting golf balls. The identification of theuser may be used to determine impact location reference data. Forexample, each user may register different frequencies when hitting agolf ball with a golf club. Accordingly, a first person's swing and hitmight only be accurately comparable to his or her own reference data.Additionally or alternatively, identification of the user may also allowthe computing system to load pre-stored user information including name,hitting records, score records, equipment records and the like. Theuser's equipment records may allow the user to identify a particularclub or type of club he or she is using. The type of golf club and thetype of golf ball used may affect the impact location determinationreference data. For example, different types of club (e.g., model,construction, etc.) may generate different sound frequencies when beinghit in different locations on its face. A driver may produce a differentsound signature than a fairway wood, for instance. Accordingly, suchclub and ball information may also provide additional parameters bywhich the impact location may be evaluated and determined.

In step 605, the computing system may determine the impact locationreference data. As described above, the impact location reference datamay be retrieved and/or defined based on a variety of factors includinguser identification, golf club type (e.g., make model, composition),golf ball type (e.g., make, model, composition) and the like and/orcombinations thereof. For example, a different set of reference data maybe defined for each combination of golf club type and golf ball type(and/or other factors). Accordingly, the computing system may furtherrequest input of the golf club type and/or golf ball type. In someexamples, the golf club type and/or the golf ball type may beautomatically determined (e.g., based on wireless communication with thegolf club and/or golf ball) or based on user input. The reference datamay be pre-loaded into the computing system. In some examples, the usermay be asked to hit multiple golf balls and to self-identify the impactlocation to generate the reference data. In some examples, a single usermay be associated with multiple sets of reference data, e.g., one setfor each type of golf club used. Additionally or alternatively,reference data may be retrieved through a network and/or from otherdevices. Thus, if a user does not have reference data predefined for aspecific type of golf club, the user may obtain reference data for otherusers that have used the specific type of golf club. Although referencedata from other users might not provide the most accurate results, thereference data may provide sufficiently accurate impact locationdeterminations given the circumstances. In some cases, impact locationdetermination results from the use of reference data from other usersmight provide may be as accurate as results from the use of the user'sown reference data.

Reference data may also be selected/retrieved using other factors inaddition to the type of golf club. For example, a user's gender, height,weight, location, handicap and the like may also be used as referencedata selection factors. Reference data may be stored in the cloud (e.g.,on a network server) or may be stored locally on a user's device. Inother examples, reference data may be passed between local devices usingshort-range wired and wireless connections.

In step 610, the computing system may detect a sound generated by theimpact of the golf ball with the face of the golf club. The computingsystem may further record the sound. In some arrangements, the computingsystem may be configured to provide instructions to the user to indicatewhen to begin a shot. Using such instructions, the computing system maybetter time when to begin recording and when the stop. Alternatively oradditionally, a user may manually indicate when a shot is to begin andwhen it has been completed.

In step 615, the computing system may process the sound signal using amathematical function such as an FFT. The FFT may be used to decompose asignal into its component frequencies. For example, using FFT on therecorded sound signal, the computing system may determine the first andsecond mode frequencies. In step 615, the computing system may alsodetermine the amplitudes of the first and second mode frequencies.Subsequently, in step 620, the determined first and second modefrequency amplitudes may be compared to the reference data to determinea location of impact.

FIG. 7 illustrates an example grid 703 dividing an area of the golf clubface 701. The grid 703 divides the area of face 701 into nine regionsand represents the level of granularity with which the impact locationmay be specified. Accordingly, each hit may be categorized into one ofthese nine regions. The reference data may specify a range of amplitudesfor the first and second mode frequencies for each of the nine regions.In one example, and as illustrated in FIG. 7, the amplitudes of thefirst mode frequency may increase from heel to toe while the amplitudesof the second mode frequency may increase from top to bottom. Empiricaltests showed that the first and second mode frequencies of the impactsound are indicative of the area in which contact was made. Based on thecorrelations between location and the amplitudes of the first and secondmode frequencies from the empirical tests, the reference data may beappropriately constructed and mapped. Additional or fewer regions on thegolf club face 701 may be defined based on needs and reference dataavailability. For example, additional empirical studies may be performedto identify the ranges of first and second mode frequencies that wouldresult from hits closer to the toe and/or heel.

In step 625, the computing system may determine an impact location ofthe shot based on the reference data and the determined first and secondmode frequencies. That is, in one example, the amplitude of the firstmode frequency may be compared to a reference range of amplitudes forfirst mode frequencies and the amplitude of the second mode frequencymay be compared to a reference range of amplitudes for the second modefrequency. The result of the comparison is configured to map the firstand second mode frequencies to the corresponding impact location. Oncethe impact location has been determined, the computing system mayfurther display a visual indication to the user in step 630.

FIG. 8 illustrates an example user interface illustrating an impactlocation indicator. In some examples, selecting the indicator 801 in theuser interface may cause the computing system to display additionalstatistics and information about the shot. For example, the additionalinformation may include a club head speed, a type of club used, adistance the ball travelled and the like. Additionally or alternatively,the computing system may also be configured to provide historical datafor all shots that had the same impact location. The display ofhistorical data may indicate historical averages when the user has shotthe ball using that impact location. The computing system may furtherprovide statistics regarding a number of shots made using that impactlocation versus other impact locations. According to one or moreaspects, the impact location indicator may be color-coded to representvarious other information including a club head speed and a frequencywith which the player or a community of players hit a golf ball at thatimpact location.

The impact location data and other shot data may be sent through anetwork to a remote golf data tracking system for storage. Alternativelyor additionally, the shot data may be stored to the mobile communicationdevice. In some examples, the user may be prompted to store the data toa network site, locally, or to delete the data. Shot information may bestored according to date, location, golf event, player and the likeand/or combinations thereof.

In some arrangements, the impact sound may be used to determine bothgolf club head speed as well as an impact location. Accordingly, anapplication executing on a mobile communication device may be equippedto provide a variety of golf shot data to a user based on the soundgenerated by the impact. Such an application and mobile communicationdevice offers a convenient and cost-effective way to analyze golf shotinformation.

The impact location may also be used to determine a player's consistencyin hitting a golf ball. For example, a user may track whether he or sheconsistently hits a golf ball at a particular area of the golf club.Alternatively, the consistency information may indicate that the usermisses a central area of the golf club, but that the impact location isinconsistent outside of the central area. Such consistency (orinconsistency) information may be useful in golf ball fitting/selection.For example, one type of ball may be better for a golfer thatconsistently misses at one (or two) areas of the face, whereas anotherball may be better if the particular player's misses are spread aroundthe golf club face. For example, if a golfer's misses (missing thepredefined best area of the golf club face) are spread among a thresholdnumber of impact areas or locations, a recommendation system mayrecommend a first type of ball. On the other hand, if the golfer'smisses are located within one or two areas of the club head, then asecond type of ball may be recommended. Consistency or inconsistency maybe measured by a predefined threshold percentage or number of shots.Accordingly, if 90% or 95% (or other percentage) of the golfer's shotsare within a predefined area (or two predefined areas), a system maydetermine that the golfer's shots are consistently within thatpredefined area (or areas). The threshold may be user-defined or may beset based on various factors such as gender, player experience, handicapand the like.

3. Example Impact Location Determination Using Motion Sensors

In addition to sound, various motion data may be detected and used toevaluate golf shot characteristics. For example, while FIGS. 6-8describe the use of sound to identify an impact location, motion datadetected using accelerometers and/or gyroscopes may also be used todetermine such shot characteristics.

FIG. 9 shows exemplary golf club head 900 that may be configured tocomprise three (3) gyroscopes. In one embodiment, a first gyroscope isconfigured to measure an angular velocity (i.e., see arrow 902) alongthe x-axis 904, a second gyroscope is configured to measure an angularvelocity (i.e., see arrow 906) along the y-axis 908, and a thirdgyroscope is configured to measure an angular velocity (i.e., see arrow910) along the z-axis 912. In one embodiment, the first gyroscope may bepositioned at around position 914 (about the center of the face alongthe x-axis 904). In yet another embodiment, the second and/or thirdgyroscope may also be located substantially at or around position 914.In yet another embodiment, one or more of the gyroscopes are along thecenter of gravity of the x-axis 904. Yet in another embodiment, one ormore of the gyroscopes may be positioned slightly below the center ofgravity. Yet in another embodiment, one or more of the gyroscopes may bepositioned inside the club shaft in the areas where the grip isattached.

Using measurements from a plurality of gyroscopes along multiple axes(for example, axes 902, 906, and 910) with knowledge of the position ofthe club just prior to the beginning of the swing (i.e., the “initialposition”), it is possible to calculate the angular orientation of theclub face at any point in the swing up to, and if desired, past theimpact with the ball. Such methods and systems are described in U.S.Pat. No. 8,257,191, entitled “Golf Clubs and Golf Club Heads HavingDigital Line and/or Other Angle Measuring Equipment,” and issued Sep. 4,2012. The content of this patent is incorporated by reference in itsentirety.

In addition to angular orientation of the club face, the gyroscopes ofclub head 900 may also provide sensor data that may be used to determinean impact location of a golf shot. The sensor data from the gyroscopesmay be used in place or in addition to the sound impact locationanalysis described above.

FIG. 10 illustrates an example method by which motion sensor data isused to calculate an impact location of a golf ball on a club face. Instep 1000, a computing system may prompt a user to strike a golf ballwith a golf club and the user may carry out the strike. As notedpreviously, the golf club with which the golf ball is struck may includeone or more sensors including accelerometers and/or gyroscopes. In step1005, the clubs accelerations and angular velocities may be determinedfrom the sensors. In one example, the sensor data may be transmittedwirelessly from the club to the computing system. The computing systemmay be, in some arrangements, a user's mobile communication device suchas a smartphone.

In step 1010, the sensor data may be edited to remove signal anomaliessuch as electrical noise, signal drop-outs, signal discontinuities andthe like. Additionally, in step 1015, the sensor data may be filtered toapply anti-aliasing, low-pass and/or band-pass filters. The applicationof anti-aliasing and/or the low-pass or band-pass filters may help toimprove the accuracy of subsequent calculations by restricting thebandwidth of the signal to a specified range. Subsequently, in step1020, the computing system may determine the response spectra for eachof the signals. The response spectra may include a set of frequenciesincluded in each of the sensor signals. Determining the response spectramay be performed in a variety of manners and using various techniquessuch as FFT, Power Spectral Density and Shock Response Spectrum. FFT, asdescribed above, is configured to separate a signal into its componentsfrequencies with varying amplitudes. Power Spectral Density, on theother hand, may also decompose a signal into component frequencies usinga stochastic process. Shock Response Spectrum provides a graphical orvisual representation of a transient acceleration input (e.g., a shockor impact signal), in terms of a single degree of freedom system. Usingany of these methods, the frequencies of a signal may be plotted againstthe amplitudes of the frequencies.

In step 1025, the response spectra may be compared to reference spectra.In one example, the reference spectra may correspond to empiricallydetermined signal data based on a population of sample shots andmanually identifying the location of impact. The population of sampleshots may be analyzed similarly to steps 1000-1020 and the responsespectra plotted against the location of impact. A correlation (e.g.,similarities) between the response spectra for any given impact locationmay be extracted from the plot or comparison and used as reference orcalibration factors. For example, in step 1030, the computing system mayidentify the impact location based on comparing the amplitudes ofspectra peaks of selected response spectra with the reference data. Somefrequencies or sensor readings may be more indicative of a particularimpact location than other frequencies or sensor readings. Accordingly,the amplitudes of these frequencies may be compared to the referencefrequencies to determine whether the response spectra is representativeof the corresponding impact location. Depending on the impact location,some sensor data may be more indicative than other sensor data and assuch, not all sensor data may be used to determine impact location atall times. For example, a response spectrum of the x-axis gyroscope maybe more indicative of an impact location in along the z-axis than they-axis gyroscope data. Similarly, a response spectrum of the z-axis maybe more indicative of an impact location along the x-axis than they-axis gyroscope data. Accordingly, if the amplitude of a specifiedfrequency on the x-axis registers above a certain threshold, the y-axisdata might not be evaluated. Other arrangements for using or notconsidering sensor data may be used to increase the efficiency of theanalysis. Impact locations may be grouped into a predefined number oflocations on a club face (see, e.g., FIG. 7). The number of discernibleimpact locations may depend on the granularity of the reference data andthe sensitivity of the sensors used to detect the various accelerationsand angular velocities.

Once the impact location has been identified, the computing system mayreport the impact location to the user in step 1035. In one example, theimpact location report may be visual as shown in FIG. 8. Alternativelyor additionally, the impact location output may include audio, textualor haptic information. In further arrangements, the impact location maybe determined using both sound and motion sensor data. The impactlocations determined using one method may be used to confirm and/orrefine the determination using the other method.

FIGS. 11A, 11B, 11C and 11D illustrate example sensor signals that maybe used to determine the impact location. FIG. 11A, for instance,illustrates a raw gyroscopic sensor signal for one of the axes shown inFIG. 9. The sensor signal may include a significant amount of noise orirrelevant data up until approximately time point 500. Accordingly,during the editing and filtering process of steps 1010 and 1015, the rawsensor signal may be reduced to an edited and filtered signal as shownin FIG. 11B. The signal may further be converted into a frequency seriesthrough application of an FFT. The resulting sensor graph is shown inFIG. 11C.

The frequency graph of the impact event of FIG. 11C may then be comparedto reference graphs or spectra as shown in FIG. 11D. The top spectrarepresents a heel shot, the middle spectra represents a central shot andthe bottom spectra represents a toe shot. In some examples, thecomparison may include a determination of how closely the signal/spectraof FIG. 11C matches one or more of the spectra of FIG. 11D. A thresholdlevel of match may be required before identifying the impact signal ascorresponding to a particular impact location. In other examples, thecomputing system might only compare certain portions of the graph suchas the frequency peak 1101. If those potions match within a thresholdlevel of similarity, the computing system may determine that the sensorsignal is representative of the corresponding impact location. Multipleportions of the response spectra may be evaluated and is not limited tothe peak frequency. Additional response spectra may be defined forvarious other impact locations including a top-heel shot, a bottom-heelshot, a central-heel shot, a top-central shot, a bottom-central shot anda central-central shot and the like. Accordingly, depending on thegranularity of the data and the ability to distinguish between portionsof the response spectra between the various impact locations, more orfewer impact locations may be recognizable.

As discussed, the response spectra may differ between types and modelsof clubs and/or the type of golf ball being struck. Accordingly, in somearrangements, the reference spectra may be selected based on the typeand/or model of club and/or ball being used. Using the various methodsand systems described herein (e.g., club head speed determination usingsound, impact location determination using sound or motion, etc.), asystem may determine both impact location as well as golf club headspeed using reference data for different combinations of golf club typeand golf ball type.

4. Golf Ball Quality/Compression Determination Using Sound Analysis

The impact between a golf ball and a striking surface may also beindicative of an amount of compression the golf ball is configured toprovide. The level of compressability of a golf ball is directly relatedto the amount of energy that is released to propel the golf ball acrossthe golf range. Accordingly, the performance and construction of golfballs may be checked to insure consistency. Additionally, manufacturersmay perform quality checks on their products to insure that the level ofcompression is within desired and/or acceptable limits. For example,different golf ball products may be designed to have different levels ofcompression when hit, and thus, consumers may expect differingperformance characteristics between the varying products.

FIG. 12 illustrates an example method whereby ball compression may beverified and quality control may be enforced. In step 1201, a computingsystem may determine an amount of ambient noise in the testing facility.The ambient noise may affect the testing parameters including a distancefrom an impact surface that a golf ball is launched/released/dropped.For example, in order to distinguish a golf ball impact from ambientnoise, the golf ball may be released from a sufficient distance suchthat the intensity of the impact is greater than the ambient noise.Accordingly, in step 1205, the computing system may determine the heightfrom which to drop each golf ball. The determination may be made basedon a predefined correlation between height and an expected intensity(e.g., volume) of the resulting impact. A different correlation may bedefined for different types of balls. Thus, the predefined correlation(e.g., a table) may be selected further based on the type of ball beingtested/evaluated.

In step 1210, the golf ball may be released or launched and theresulting impact sound may be recorded by the computing system. Once thesound is recorded, the sound signal may be processed to extract thecomponent frequencies, as discussed herein. The computing system maythen determine a reference frequency or reference frequencies with whichto evaluate the recorded sound and component frequencies thereof. Thereference frequency may be selected based on the height from which theball was released as well as the type of golf ball. In one example, theamplitude of one or more reference frequencies may be compared with theamplitude of the corresponding one or more frequencies of the impactsignal. If the amplitudes are determined to match (e.g., within a % oramount of difference of the reference frequency), then the computingsystem may determine that the golf ball is within the desiredoperational parameters (e.g., as shown in step 1220). Otherwise, thefrequency characteristics may be identified as a non-match and the golfball may be identified as failing the quality check.

In addition or as an alternative to frequency amplitude, the computingsystem may evaluate the signal for frequency peaks. For example, afrequency peak may correspond to a frequency at which the signalregistered the greatest amplitude. Thus, if the frequency peak isregistered at a first frequency, the computing system may determine thatthe golf ball experienced a first level of compression. Alternative, ifthe frequency peak registers at a second frequency, the computing systemmay determine that the golf ball experienced a second level ofcompression. Still further, the computing system may base itsdetermination of one or more golf equipment characteristics on adetected frequency or amplitude shift in the signal (audio, motionsensor, etc.). For example, a 40 Hz shift in the peak frequency maycorrespond to a 0.3 mm increase or decrease in compression. In anotherexample, a decibel shift may correspond to a specified amount ofincrease or decrease in compression. The shifts may also correspond to ashift in location of the impact location, in some arrangements.Accordingly, if the a first impact location or first level ofcompression is known or otherwise determined, a subsequent impactlocation or level of compression may be determined by adjusting thefirst impact location or level of compression based on an amountcorresponding to the shift in frequency or amplitude.

In step 1225, the computing system may further generate an output suchas a quality indication sound or visual indicator. In one example, theoutput may include a textual message specifying that the quality isconfirmed. In another example, the output may comprise a display of aparticular color (e.g., GREEN for quality confirmed and RED for golfballs that did not pass the quality check). In yet other examples, asound may be played when a golf ball has not passed a quality checkwhile no sound may be played when the golf ball passes the qualitycheck.

FIG. 13 illustrates an example ball testing and sort device 1300configured to quality check each golf ball 1301 and to sort the golfballs, e.g., golf ball 1301 into one of the Passed storage 1303 and theNot Passaged storage 1305. For example, a sorting arm may be configuredto move the golf ball 1301 (after it has been dropped) to one ofmultiple openings leading to each of the storages 1303 and 1305. Thegolf ball 1301 may be held by a set of claws (not shown) or othersecuring mechanism at a top of the device 1300. The golf ball 1301 maythen be released toward surface 1311. The impact between the ball 1301and surface 1311 may be recorded using microphone 1307. The result ofball 1301's quality check may be conveyed on display 1309. Alternativelyor additionally, the quality check results may be provided through audioor haptic methods. The golf ball 1301 may be suspended above surface1311 at a specified distance. Neck portion 1313 of device 1300 may beexpandable and retractable such that the height of the ball may bemodified. As noted above, if the ambient noise is too great, the heightof the ball may be increased.

As described herein, the impact between a golf ball and another surfacesuch as a golf club face or other type of impact surface may beindicative of a variety of golf equipment information including impactlocation, compression level and club head speed. The characteristics maybe calculated using a computing device based on sensor data, includingmotion sensor data and/or sound data. Other types of equipmentinformation may be derived from such sensor data and is not limited tothe data output described herein.

Reference data for determining impact location, golf club head speed,golf ball compression or quality and other golf equipmentcharacteristics may be predefined through user input or a population oftest results and/or created on-the-fly through detection of actual usershots. In one example, for one or more shots, the user may have theoption to input the type of club used, the type of ball hit and theimpact location, golf club head speed, compression level or other golfequipment characteristic. Other factors that may be specified mayinclude type of terrain, weather and geographic location. These shotsmay be test shots, shots taken at a driving range, shots taken during agolf game and the like and/or combinations thereof. The manuallyspecified information may then be used to build a database (e.g., storedin association with one another) and to generate referenceinformation/characteristics (e.g., impact location, golf club headspeed, compression level, etc.) for a particular combination ofequipment. Accordingly, a computing system may be configured toself-learn reference information to build such a database over time.Shot information from a plurality of users may also be combined toformulate a set of reference characteristics. For example, theuser-specified golf equipment characteristics and attributes (e.g., typeof equipment) may be transmitted to a tracking server for adding to areference database. Alternatively or additionally, a reference databasemight only be built specifically for each individual user. For example,the reference data for one user might not be used for another user.

In some arrangements and according to aspects described herein,reference data may include sound signatures for different ball and clubcombinations. For example, for a given golf ball type and golf club typecombination, the sound generated from an impact at a particular point onthe club head face may have the same or substantially the same soundsignal or signal shape irrespective of the club head speed. However, theclub head speed may affect the volume/intensity of the sound and thus,may be reflected in the amplitude of the signal, while the overallsignal shape may remain consistent or unchanged. Impact the golf ballwith different locations on the golf club face, on the other hand, mayalter the expected signal shape. Accordingly, each impact location for agiven golf ball type and golf club type combination may be associatedwith a different reference signal shape.

Using such sound signatures, an impact between a given golf ball andgolf club head may be compared against a library or database of soundsignatures for hits using that golf ball and golf club head combination.In one example, Fast Fourier Transform analysis may be applied. Becausethe overall shapes of the sound signals may differ depending on thelocation on the face where the club head and ball meet, the best matchfor the general shape of the unknown contact sound signal (e.g., thecollision being analyzed) may be identified from a library subset ofknown impact locations for that club/ball (using the Fast FourierTransform analysis). The match may represent the position on the facewhere the ball and club head collided. Furthermore, by looking at theamplitudes of the signals generated for both the unknown signal (e.g.,the signal/hit being analyzed) and the known reference signal at theimpact location, a system may also determine and/or provide anestimation of the club head speed during the unknown contact. Forexample, the club head speed may be determined (e.g., estimated) bylooking at the amplitudes of one or more of the sound signature peak(s)for the unknown contact and comparing that amplitude(s) with the storedamplitude(s) at the known speeds (optionally also using extrapolationand interpolation for amplitudes outside of the known reference points).

As described, sound and motion sensor signals may be indicative ofimpact location, golf ball compression and golf club head speed. Suchsignals may also provide information and be used to determine other golfequipment characteristics including material hardness, whether golfequipment (e.g., golf club) material has delaminated from each other,whether layers in the equipment include voids or pores, and/ordifference in hardness of layers. Layers may refer to layers in any ofgolf equipment including a golf club head and a golf ball. For example,a golf ball may be tested for quality and/or consistency prior tocomplete construction (e.g., a golf ball precursor). In a particularexample, a golf ball inner core and a first layer (e.g., a mantle) maybe tested for consistency or quality, prior to attaching or forming theouter layer.

Still further, the various equipment and/or performance characteristicssuch as swing speed (e.g., club head speed), impact location and thelike may be used to determine the quality of a user's shot. For example,if the user hits a golf ball with a central area of the golf club head(e.g., the “sweet spot”), a computing device may advise the user that heor she has made an excellent or high quality shot (e.g., good hit).Additionally, the farther away from the central area (or otherpredefined area), the lower the quality of shot (e.g., an OK hit, adecent hit, a bad hit). The equipment and/or performance characteristicsmay be combined to determine the quality of the shot. For example, ahighest quality shot may be defined by a high club head speed andimpacting a predefined (e.g., central area) of the golf club head. Golfshot quality may be defined in a variety of manners including based on arating scale of 1-10, a color rating scale (green for good, yellow forOK and red for bad).

CONCLUSION

While the invention has been described in detail in terms of specificexamples including presently preferred modes of carrying out theinvention, those skilled in the art will appreciate that there arenumerous variations and permutations of the above described systems andmethods. Thus, the spirit and scope of the invention should be construedbroadly as set forth in the appended claims.

We claim:
 1. A method of determining a golf club head swing speed, themethod comprising: receiving sound data generated from striking aplurality of golf balls using a golf club, wherein the golf clubcomprises a golf club head having a striking face, a shaft, and a grip,wherein the plurality of golf balls comprises at least a first golf balland a second golf ball, wherein the first golf ball comprises a firstset of characteristics to generate a first sound signal having at leasta first predefined frequency when struck by the golf club at a firstpredefined golf club head swing speed, wherein the second golf ballcomprises a second set of characteristics to generate a second soundsignal having at least a second predefined frequency when struck by thegolf club at a second predefined golf club head swing speed, wherein acomputing device receives sound signal data generated from hitting thefirst and second golf balls with the golf club, wherein the computingdevice analyzes the sound signal data generated from hitting the firstand second golf balls with the golf club to detect either the first orsecond predefined frequency, wherein if the first or secondpredetermined frequency is detected, the computing device displays thepredetermined golf club head swing speed associated with the first orsecond predetermined frequency.
 2. The method of claim 1, whereinwherein the plurality of golf balls comprises a third and fourth golfball, wherein the third golf ball comprises a third set ofcharacteristics to generate a third sound signal having at least a thirdpredefined frequency when struck by the golf club at a third predefinedgolf club head swing speed, wherein the fourth golf ball comprises afourth set of characteristics to generate a fourth sound signal havingat least a fourth predefined frequency when struck by the golf club at afourth predefined golf club head swing speed, wherein if the third orfourth predetermined frequency is detected, the computing devicedisplays the golf club head swing speed associated with the third orfourth predetermined frequency.
 3. The method of claim 2, wherein all ofthe sound data generated has both frequency and an amplitude.
 4. Themethod of claim 1, wherein the method does not use a motion sensor orspeed gun.
 5. The method of claim 3, wherein the predetermined golf clubhead swing speed of the fourth golf ball is lower than the predeterminedgolf club head swing speed of the third golf ball, which is lower thanthe predetermined golf club head swing speed of the second golf ball,which is lower than the predetermined golf club head swing speed of thefirst golf ball.
 6. The method of claim 2, wherein the computing systemmay recommend a model of golf ball based on the golf club head swingspeed.
 7. The method of claim 1, wherein the plurality of golf ballscomprises ten or fewer golf balls.